1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * DRM driver for MIPI DBI compatible display panels 4 * 5 * Copyright 2022 Noralf Trønnes 6 */ 7 8 #include <linux/backlight.h> 9 #include <linux/delay.h> 10 #include <linux/firmware.h> 11 #include <linux/gpio/consumer.h> 12 #include <linux/module.h> 13 #include <linux/property.h> 14 #include <linux/regulator/consumer.h> 15 #include <linux/spi/spi.h> 16 17 #include <drm/drm_atomic_helper.h> 18 #include <drm/drm_drv.h> 19 #include <drm/drm_fbdev_generic.h> 20 #include <drm/drm_gem_atomic_helper.h> 21 #include <drm/drm_gem_dma_helper.h> 22 #include <drm/drm_managed.h> 23 #include <drm/drm_mipi_dbi.h> 24 #include <drm/drm_modes.h> 25 #include <drm/drm_modeset_helper.h> 26 27 #include <video/mipi_display.h> 28 29 static const u8 panel_mipi_dbi_magic[15] = { 'M', 'I', 'P', 'I', ' ', 'D', 'B', 'I', 30 0, 0, 0, 0, 0, 0, 0 }; 31 32 /* 33 * The display controller configuration is stored in a firmware file. 34 * The Device Tree 'compatible' property value with a '.bin' suffix is passed 35 * to request_firmware() to fetch this file. 36 */ 37 struct panel_mipi_dbi_config { 38 /* Magic string: panel_mipi_dbi_magic */ 39 u8 magic[15]; 40 41 /* Config file format version */ 42 u8 file_format_version; 43 44 /* 45 * MIPI commands to execute when the display pipeline is enabled. 46 * This is used to configure the display controller. 47 * 48 * The commands are stored in a byte array with the format: 49 * command, num_parameters, [ parameter, ...], command, ... 50 * 51 * Some commands require a pause before the next command can be received. 52 * Inserting a delay in the command sequence is done by using the NOP command with one 53 * parameter: delay in miliseconds (the No Operation command is part of the MIPI Display 54 * Command Set where it has no parameters). 55 * 56 * Example: 57 * command 0x11 58 * sleep 120ms 59 * command 0xb1 parameters 0x01, 0x2c, 0x2d 60 * command 0x29 61 * 62 * Byte sequence: 63 * 0x11 0x00 64 * 0x00 0x01 0x78 65 * 0xb1 0x03 0x01 0x2c 0x2d 66 * 0x29 0x00 67 */ 68 u8 commands[]; 69 }; 70 71 struct panel_mipi_dbi_commands { 72 const u8 *buf; 73 size_t len; 74 }; 75 76 static struct panel_mipi_dbi_commands * 77 panel_mipi_dbi_check_commands(struct device *dev, const struct firmware *fw) 78 { 79 const struct panel_mipi_dbi_config *config = (struct panel_mipi_dbi_config *)fw->data; 80 struct panel_mipi_dbi_commands *commands; 81 size_t size = fw->size, commands_len; 82 unsigned int i = 0; 83 84 if (size < sizeof(*config) + 2) { /* At least 1 command */ 85 dev_err(dev, "config: file size=%zu is too small\n", size); 86 return ERR_PTR(-EINVAL); 87 } 88 89 if (memcmp(config->magic, panel_mipi_dbi_magic, sizeof(config->magic))) { 90 dev_err(dev, "config: Bad magic: %15ph\n", config->magic); 91 return ERR_PTR(-EINVAL); 92 } 93 94 if (config->file_format_version != 1) { 95 dev_err(dev, "config: version=%u is not supported\n", config->file_format_version); 96 return ERR_PTR(-EINVAL); 97 } 98 99 drm_dev_dbg(dev, DRM_UT_DRIVER, "size=%zu version=%u\n", size, config->file_format_version); 100 101 commands_len = size - sizeof(*config); 102 103 while ((i + 1) < commands_len) { 104 u8 command = config->commands[i++]; 105 u8 num_parameters = config->commands[i++]; 106 const u8 *parameters = &config->commands[i]; 107 108 i += num_parameters; 109 if (i > commands_len) { 110 dev_err(dev, "config: command=0x%02x num_parameters=%u overflows\n", 111 command, num_parameters); 112 return ERR_PTR(-EINVAL); 113 } 114 115 if (command == 0x00 && num_parameters == 1) 116 drm_dev_dbg(dev, DRM_UT_DRIVER, "sleep %ums\n", parameters[0]); 117 else 118 drm_dev_dbg(dev, DRM_UT_DRIVER, "command %02x %*ph\n", 119 command, num_parameters, parameters); 120 } 121 122 if (i != commands_len) { 123 dev_err(dev, "config: malformed command array\n"); 124 return ERR_PTR(-EINVAL); 125 } 126 127 commands = devm_kzalloc(dev, sizeof(*commands), GFP_KERNEL); 128 if (!commands) 129 return ERR_PTR(-ENOMEM); 130 131 commands->len = commands_len; 132 commands->buf = devm_kmemdup(dev, config->commands, commands->len, GFP_KERNEL); 133 if (!commands->buf) 134 return ERR_PTR(-ENOMEM); 135 136 return commands; 137 } 138 139 static struct panel_mipi_dbi_commands *panel_mipi_dbi_commands_from_fw(struct device *dev) 140 { 141 struct panel_mipi_dbi_commands *commands; 142 const struct firmware *fw; 143 const char *compatible; 144 char fw_name[40]; 145 int ret; 146 147 ret = of_property_read_string_index(dev->of_node, "compatible", 0, &compatible); 148 if (ret) 149 return ERR_PTR(ret); 150 151 snprintf(fw_name, sizeof(fw_name), "%s.bin", compatible); 152 ret = request_firmware(&fw, fw_name, dev); 153 if (ret) { 154 dev_err(dev, "No config file found for compatible '%s' (error=%d)\n", 155 compatible, ret); 156 157 return ERR_PTR(ret); 158 } 159 160 commands = panel_mipi_dbi_check_commands(dev, fw); 161 release_firmware(fw); 162 163 return commands; 164 } 165 166 static void panel_mipi_dbi_commands_execute(struct mipi_dbi *dbi, 167 struct panel_mipi_dbi_commands *commands) 168 { 169 unsigned int i = 0; 170 171 if (!commands) 172 return; 173 174 while (i < commands->len) { 175 u8 command = commands->buf[i++]; 176 u8 num_parameters = commands->buf[i++]; 177 const u8 *parameters = &commands->buf[i]; 178 179 if (command == 0x00 && num_parameters == 1) 180 msleep(parameters[0]); 181 else if (num_parameters) 182 mipi_dbi_command_stackbuf(dbi, command, parameters, num_parameters); 183 else 184 mipi_dbi_command(dbi, command); 185 186 i += num_parameters; 187 } 188 } 189 190 static void panel_mipi_dbi_enable(struct drm_simple_display_pipe *pipe, 191 struct drm_crtc_state *crtc_state, 192 struct drm_plane_state *plane_state) 193 { 194 struct mipi_dbi_dev *dbidev = drm_to_mipi_dbi_dev(pipe->crtc.dev); 195 struct mipi_dbi *dbi = &dbidev->dbi; 196 int ret, idx; 197 198 if (!drm_dev_enter(pipe->crtc.dev, &idx)) 199 return; 200 201 drm_dbg(pipe->crtc.dev, "\n"); 202 203 ret = mipi_dbi_poweron_conditional_reset(dbidev); 204 if (ret < 0) 205 goto out_exit; 206 if (!ret) 207 panel_mipi_dbi_commands_execute(dbi, dbidev->driver_private); 208 209 mipi_dbi_enable_flush(dbidev, crtc_state, plane_state); 210 out_exit: 211 drm_dev_exit(idx); 212 } 213 214 static const struct drm_simple_display_pipe_funcs panel_mipi_dbi_pipe_funcs = { 215 DRM_MIPI_DBI_SIMPLE_DISPLAY_PIPE_FUNCS(panel_mipi_dbi_enable), 216 }; 217 218 DEFINE_DRM_GEM_DMA_FOPS(panel_mipi_dbi_fops); 219 220 static const struct drm_driver panel_mipi_dbi_driver = { 221 .driver_features = DRIVER_GEM | DRIVER_MODESET | DRIVER_ATOMIC, 222 .fops = &panel_mipi_dbi_fops, 223 DRM_GEM_DMA_DRIVER_OPS_VMAP, 224 .debugfs_init = mipi_dbi_debugfs_init, 225 .name = "panel-mipi-dbi", 226 .desc = "MIPI DBI compatible display panel", 227 .date = "20220103", 228 .major = 1, 229 .minor = 0, 230 }; 231 232 static int panel_mipi_dbi_get_mode(struct mipi_dbi_dev *dbidev, struct drm_display_mode *mode) 233 { 234 struct device *dev = dbidev->drm.dev; 235 u16 hback_porch, vback_porch; 236 int ret; 237 238 ret = of_get_drm_panel_display_mode(dev->of_node, mode, NULL); 239 if (ret) { 240 dev_err(dev, "%pOF: failed to get panel-timing (error=%d)\n", dev->of_node, ret); 241 return ret; 242 } 243 244 mode->type = DRM_MODE_TYPE_DRIVER | DRM_MODE_TYPE_PREFERRED; 245 246 hback_porch = mode->htotal - mode->hsync_end; 247 vback_porch = mode->vtotal - mode->vsync_end; 248 249 /* 250 * Make sure width and height are set and that only back porch and 251 * pixelclock are set in the other timing values. Also check that 252 * width and height don't exceed the 16-bit value specified by MIPI DCS. 253 */ 254 if (!mode->hdisplay || !mode->vdisplay || mode->flags || 255 mode->hsync_end > mode->hdisplay || (hback_porch + mode->hdisplay) > 0xffff || 256 mode->vsync_end > mode->vdisplay || (vback_porch + mode->vdisplay) > 0xffff) { 257 dev_err(dev, "%pOF: panel-timing out of bounds\n", dev->of_node); 258 return -EINVAL; 259 } 260 261 /* The driver doesn't use the pixel clock but it is mandatory so fake one if not set */ 262 if (!mode->clock) 263 mode->clock = mode->htotal * mode->vtotal * 60 / 1000; 264 265 dbidev->top_offset = vback_porch; 266 dbidev->left_offset = hback_porch; 267 268 return 0; 269 } 270 271 static int panel_mipi_dbi_spi_probe(struct spi_device *spi) 272 { 273 struct device *dev = &spi->dev; 274 struct drm_display_mode mode; 275 struct mipi_dbi_dev *dbidev; 276 struct drm_device *drm; 277 struct mipi_dbi *dbi; 278 struct gpio_desc *dc; 279 int ret; 280 281 dbidev = devm_drm_dev_alloc(dev, &panel_mipi_dbi_driver, struct mipi_dbi_dev, drm); 282 if (IS_ERR(dbidev)) 283 return PTR_ERR(dbidev); 284 285 dbi = &dbidev->dbi; 286 drm = &dbidev->drm; 287 288 ret = panel_mipi_dbi_get_mode(dbidev, &mode); 289 if (ret) 290 return ret; 291 292 dbidev->regulator = devm_regulator_get(dev, "power"); 293 if (IS_ERR(dbidev->regulator)) 294 return dev_err_probe(dev, PTR_ERR(dbidev->regulator), 295 "Failed to get regulator 'power'\n"); 296 297 dbidev->io_regulator = devm_regulator_get(dev, "io"); 298 if (IS_ERR(dbidev->io_regulator)) 299 return dev_err_probe(dev, PTR_ERR(dbidev->io_regulator), 300 "Failed to get regulator 'io'\n"); 301 302 dbidev->backlight = devm_of_find_backlight(dev); 303 if (IS_ERR(dbidev->backlight)) 304 return dev_err_probe(dev, PTR_ERR(dbidev->backlight), "Failed to get backlight\n"); 305 306 dbi->reset = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH); 307 if (IS_ERR(dbi->reset)) 308 return dev_err_probe(dev, PTR_ERR(dbi->reset), "Failed to get GPIO 'reset'\n"); 309 310 /* Multiple panels can share the "dc" GPIO, but only if they are on the same SPI bus! */ 311 dc = devm_gpiod_get_optional(dev, "dc", GPIOD_OUT_LOW | GPIOD_FLAGS_BIT_NONEXCLUSIVE); 312 if (IS_ERR(dc)) 313 return dev_err_probe(dev, PTR_ERR(dc), "Failed to get GPIO 'dc'\n"); 314 315 ret = mipi_dbi_spi_init(spi, dbi, dc); 316 if (ret) 317 return ret; 318 319 if (device_property_present(dev, "write-only")) 320 dbi->read_commands = NULL; 321 322 dbidev->driver_private = panel_mipi_dbi_commands_from_fw(dev); 323 if (IS_ERR(dbidev->driver_private)) 324 return PTR_ERR(dbidev->driver_private); 325 326 ret = mipi_dbi_dev_init(dbidev, &panel_mipi_dbi_pipe_funcs, &mode, 0); 327 if (ret) 328 return ret; 329 330 drm_mode_config_reset(drm); 331 332 ret = drm_dev_register(drm, 0); 333 if (ret) 334 return ret; 335 336 spi_set_drvdata(spi, drm); 337 338 drm_fbdev_generic_setup(drm, 0); 339 340 return 0; 341 } 342 343 static void panel_mipi_dbi_spi_remove(struct spi_device *spi) 344 { 345 struct drm_device *drm = spi_get_drvdata(spi); 346 347 drm_dev_unplug(drm); 348 drm_atomic_helper_shutdown(drm); 349 } 350 351 static void panel_mipi_dbi_spi_shutdown(struct spi_device *spi) 352 { 353 drm_atomic_helper_shutdown(spi_get_drvdata(spi)); 354 } 355 356 static int __maybe_unused panel_mipi_dbi_pm_suspend(struct device *dev) 357 { 358 return drm_mode_config_helper_suspend(dev_get_drvdata(dev)); 359 } 360 361 static int __maybe_unused panel_mipi_dbi_pm_resume(struct device *dev) 362 { 363 drm_mode_config_helper_resume(dev_get_drvdata(dev)); 364 365 return 0; 366 } 367 368 static const struct dev_pm_ops panel_mipi_dbi_pm_ops = { 369 SET_SYSTEM_SLEEP_PM_OPS(panel_mipi_dbi_pm_suspend, panel_mipi_dbi_pm_resume) 370 }; 371 372 static const struct of_device_id panel_mipi_dbi_spi_of_match[] = { 373 { .compatible = "panel-mipi-dbi-spi" }, 374 {}, 375 }; 376 MODULE_DEVICE_TABLE(of, panel_mipi_dbi_spi_of_match); 377 378 static const struct spi_device_id panel_mipi_dbi_spi_id[] = { 379 { "panel-mipi-dbi-spi", 0 }, 380 { }, 381 }; 382 MODULE_DEVICE_TABLE(spi, panel_mipi_dbi_spi_id); 383 384 static struct spi_driver panel_mipi_dbi_spi_driver = { 385 .driver = { 386 .name = "panel-mipi-dbi-spi", 387 .owner = THIS_MODULE, 388 .of_match_table = panel_mipi_dbi_spi_of_match, 389 .pm = &panel_mipi_dbi_pm_ops, 390 }, 391 .id_table = panel_mipi_dbi_spi_id, 392 .probe = panel_mipi_dbi_spi_probe, 393 .remove = panel_mipi_dbi_spi_remove, 394 .shutdown = panel_mipi_dbi_spi_shutdown, 395 }; 396 module_spi_driver(panel_mipi_dbi_spi_driver); 397 398 MODULE_DESCRIPTION("MIPI DBI compatible display panel driver"); 399 MODULE_AUTHOR("Noralf Trønnes"); 400 MODULE_LICENSE("GPL"); 401